In 2007, shortly after vice-president Joe Biden learned that his eldest son would be deployed to Iraq, the then-presidential hopeful turned to a modest crowd at the Iowa state fair and admitted that he didn't want Beau to go. Beau arrived in Iraq the following year. Though he returned home safely ... his health deteriorated, and he was diagnosed with brain cancer. Less than two years later, he died at the age of 46. A new book ... suggests a possible link between his illness and service. Based on clusters of similar cases, scientific studies and expert opinions, author Joseph Hickman proposes in The Burn Pits: The Poisoning of America's Soldiers that [some] US service members in Iraq and Afghanistan confronted ... respiratory issues relating to their burn pit exposure. Others likely developed more life-threatening conditions such as cancers, Hickman contends, because of what the burn pits were built on top of: the remnants of Saddam Hussein's chemical weapons program. The Pentagon ordered the use of open-air burn pits to dispose of the wars' massive volume of waste. Among the other hazardous items service members recall being burned are: petroleum, oil, rubber, tires, plastic, styrofoam, batteries, appliances, electrical equipment, pesticides, aerosol cans, oil, explosives, casings, medical waste and animal and human carcasses. The VA does does not acknowledge a link between burn pits and long-term health problems. Of the 500 people included in Hickman's burn pit study, the VA denied disability benefits to over 90% of them.